24 volt windlass on 12 volt boat? Anyone done this?

[Kukri]

The new to me boat has good 12v electrics. If I were starting from scratch I would wire for 24v but I’m not.

I want to fit an electric windlass, probably with its own battery in the forecabin, to keep the heavy cable runs short. Many of the windlasses that I see are 24v.

The problem seems to be charging, particularly as one normally runs the engine when using the windlass. One would need a very beefy step up transformer. Or is there another way?

Has anyone done this?

 

[noelex]

The amphour consumption of the windlass is not very high so the 12 to 24v charger need not be very large. Mastervolt among others make chargers that would be suitable.

24v windlasses are available in larger sizes than 12v models so if you have a bigger boat they do become an attractive proposition, otherwise I would keep it simple and fit a 12v windlass.

 

[Kukri]

Thank you!

 

[lw395]

Running a (relatively) low power battery-to-battery charger is a good solution, as it avoids the need for long heavy cables.
The downside is that assistance from the alternator is limited to the charger's power.

There have been many threads about sizing windlass cables, it's not trivial. Or cheap.

 

[bigwow]

Running a (relatively) low power battery-to-battery charger is a good solution, as it avoids the need for long heavy cables.
The downside is that assistance from the alternator is limited to the charger's power.

There have been many threads about sizing windlass cables, it's not trivial. Or cheap.

Cheaper to source cable from welding equipment suppliers.

 

[Lon nan Gruagach]

Charge a pair of batteries in parallel (12V) use in series (24V)
All you need is a 2 pole change over solenoid (probably be able to use second winch control solenoid for that) run from the same control signal.

 

[sarabande]

If you have a preference for 24v, could you add a 24v alternator to run e.g. a fridge/watermaker/windlass/radar/etc, and leave the 12v system as is ?

Cabling to the windlass batteries at the sharp end would be quite a bit smaller.

 

[Kukri]

If you have a preference for 24v, could you add a 24v alternator to run e.g. a fridge/watermaker/windlass/radar/etc, and leave the 12v system as is ?

Cabling to the windlass batteries at the sharp end would be quite a bit smaller.

Radar and fridge are 12v!

 

[moomba]

you would put 2 batteries up forward in series to make 24 volts and have a step up transformer to charge those batteries your cable run to charge does not need to be beefy only your wires from battery to windlass , and as the run is very short it can be less also as 24 volts your am page is halfed so your cabling can reflect this
I have a 24 volt boat and just rewired it , and have a step down transformer for 12 volts ,for those pesky 12 volt items
for cables and info try 12 volt planet and on the web some good info and great products or there is a great u tube channel by pacific yacht systems for everything about rewiring a boat

 

[Yngmar]

A separate battery bank in the bow just to save on a bit of thick cable going forward just doesn't make much sense.

If you're just doing a bit of settled weather anchoring, a separate windlass battery bank that is slowly charged by the alternator can work. But charging would be with a VSR or in case of a 24V windlass on a 12V boat with a B2B charger. The VSR/B2B charger plus additional battery bank will easily exceed the cost and weight of the thick cables running to the bow. Worse, it's weight in the bow instead of distributed along the length of the boat. If your boat was so long the wire run was a real problem, it would most likely already be a 24V boat anyways.

And if you're doing serious anchoring, you will sooner or later end up in a situation where you need to re-anchor a bunch of times in short order, and the very last thing you want in an already hairy situation is a dead windlass battery that cannot be fed directly from the alternator output (buffered by the main battery bank of the boat).

Feeding a 24V windlass directly from a 12V source (alternator or house bank) would require a very beefy DC boost converter. Our windlass is rated at 1000W and I expect it will draw 2-3 times that when starting or stalled (although the latter should be prevented by the windlass clutch). Such converters can be found, but aren't cheap, are bulky and will require cooling.

So in short, fitting a 12V windlass with the long cable run is likely to be the cheapest, most lightweight and simplest solution.

 

[Frank Holden]

A separate battery bank in the bow just to save on a bit of thick cable going forward just doesn't make much sense.

If you're just doing a bit of settled weather anchoring, a separate windlass battery bank that is slowly charged by the alternator can work. But charging would be with a VSR or in case of a 24V windlass on a 12V boat with a B2B charger. The VSR/B2B charger plus additional battery bank will easily exceed the cost and weight of the thick cables running to the bow. Worse, it's weight in the bow instead of distributed along the length of the boat. If your boat was so long the wire run was a real problem, it would most likely already be a 24V boat anyways.

And if you're doing serious anchoring, you will sooner or later end up in a situation where you need to re-anchor a bunch of times in short order, and the very last thing you want in an already hairy situation is a dead windlass battery that cannot be fed directly from the alternator output (buffered by the main battery bank of the boat).

Feeding a 24V windlass directly from a 12V source (alternator or house bank) would require a very beefy DC boost converter. Our windlass is rated at 1000W and I expect it will draw 2-3 times that when starting or stalled (although the latter should be prevented by the windlass clutch). Such converters can be found, but aren't cheap, are bulky and will require cooling.

So in short, fitting a 12V windlass with the long cable run is likely to be the cheapest, most lightweight and simplest solution.

I couldn't have said it better myself...... :encouragement:

 

[William_H]

If you are determined on using a 24v winch on a 12v system boat. I think the thing to do would be to try the winch on 12v supply. Contrary to what you might imagine motors particularly DC motors have a peculiar current draw pattern such that if it runs slower it will draw more current so tend to recover some of the power loss. So if we talk about a 24v heating element or incandescent lamp on 12v we divide the power on 24v by 4. ie half the current at half the volts. But our motor will draw a lot more current running slowly so tend to recover some of that power. So particularly if you had a lightish anchor and a fairly powerful winch performance may be oK.
If it is not then run cables from the engine bay. Fit another 12v battery (or use part of existing house battery) and switching as suggested so that it is charged normally (and can bhe part of house battery system) but switched in series with engine battery for winch operation. With engine running you will have alternator charging the lower 12v half of the 24v system.
good luck ol'will

 

[Neeves]

A separate battery bank in the bow just to save on a bit of thick cable going forward just doesn't make much sense.

If you're just doing a bit of settled weather anchoring, a separate windlass battery bank that is slowly charged by the alternator can work. But charging would be with a VSR or in case of a 24V windlass on a 12V boat with a B2B charger. The VSR/B2B charger plus additional battery bank will easily exceed the cost and weight of the thick cables running to the bow. Worse, it's weight in the bow instead of distributed along the length of the boat. If your boat was so long the wire run was a real problem, it would most likely already be a 24V boat anyways.

And if you're doing serious anchoring, you will sooner or later end up in a situation where you need to re-anchor a bunch of times in short order, and the very last thing you want in an already hairy situation is a dead windlass battery that cannot be fed directly from the alternator output (buffered by the main battery bank of the boat).

Feeding a 24V windlass directly from a 12V source (alternator or house bank) would require a very beefy DC boost converter. Our windlass is rated at 1000W and I expect it will draw 2-3 times that when starting or stalled (although the latter should be prevented by the windlass clutch). Such converters can be found, but aren't cheap, are bulky and will require cooling.

So in short, fitting a 12V windlass with the long cable run is likely to be the cheapest, most lightweight and simplest solution.

I agree and with Frank.

I don't know how much batteries cost where you are but surely heavier duty wiring is cheaper - unless of course your yacht is humongous. The additional complexity - might be simple to you - would deter me (and a buyer of your yacht). And you want to add batteries to possible the wettest part of your yacht. Not to mention even more weight in the bow. And your back-up if the windlass battery fails?

If you want extra battery facility - add them to the house bank (as you can run your engines any time you anchor or retrieve).

12v systems are 'normal', everywhere - 24v systems less common. Spares, support??

Why make a simple system overly complex and possibly expensive.

Jonathan

 

[john_morris_uk]

Reading this thread through, I’m anxious about the number of references to ‘transforming’ 12V to 24v and the reverse. You can’t just ‘transform’ DC. It’s a complex process to step up a DC voltage (and much easier to step it down!) high current demand make the job even more challenging.

And I agree with Frank. The cost of two heavy duty cables is minuscule compared to ‘step up devices or extra batteries and charging systems’.

 

[lw395]

Reading this thread through, I’m anxious about the number of references to ‘transforming’ 12V to 24v and the reverse. You can’t just ‘transform’ DC. It’s a complex process to step up a DC voltage (and much easier to step it down!) high current demand make the job even more challenging.

And I agree with Frank. The cost of two heavy duty cables is minuscule compared to ‘step up devices or extra batteries and charging systems’.

The cost of cable is not trivial.
On a big boat, cable which is truly adequate might cost more than two batteries.
Charging 24V batteries from 12V is fairly mundane, at the current needed to keep a battery charged and replenish the use from a pick winch (and/or thruster) it's not expensive.
It's a process as complex or simple as buying a black box from a supplier you trust.
Blathering generalities is not helpful.
To counter what another poster said, 24V equipment is common as muck, lorries are full of it.
The proper thing to do is to fully cost the various schemes and weigh up the pros and cons.
The hidden cost might be the work involved in installing adequate cables which the boat isn't designed around.
I'd guess a 12V windlass with simple fat cables might be the cheapest and best solution, but if one wants a big powerful windlass to cope with a big anchor and lots of chain, maybe not.

 

[Kukri]

Thanks, everyone!

I’m not going to do it!

 

[moomba]

The cost of cable is not trivial.
On a big boat, cable which is truly adequate might cost more than two batteries.
Charging 24V batteries from 12V is fairly mundane, at the current needed to keep a battery charged and replenish the use from a pick winch (and/or thruster) it's not expensive.
It's a process as complex or simple as buying a black box from a supplier you trust.
Blathering generalities is not helpful.
To counter what another poster said, 24V equipment is common as muck, lorries are full of it.
The proper thing to do is to fully cost the various schemes and weigh up the pros and cons.
The hidden cost might be the work involved in installing adequate cables which the boat isn't designed around.
I'd guess a 12V windlass with simple fat cables might be the cheapest and best solution, but if one wants a big powerful windlass to cope with a big anchor and lots of chain, maybe not.

Agree wholeheartedly , I have a 24 volt boat with a 1500 watt 24 volt windlass rewired to boat with proper tinned cable (small fortune , Due to marine equipment for leisure boats being 12 volt more common , I also installed a 24 volt to 12 volt reducer wired with appropriate fusing , this now gives me a 24 volt control panel and a 12 volt control panel to wire to if need be , very simple and around 60 pounds for a good make of reducer , the same going to other way 12 volts to 24 volts , I find 24 volt pumps and alternators and fans easy to find and in some cases cheaper as they don't sell and are always on sale , but marine electronics is a bastardo to get in 24 volts , so hence the 12 volt panel , if you wire correctly , and fuse to protect circuits then it is safe and easy , also to reiterate the point heavy duty tinned cable for batteries for a long run is a small fortune remember you have to get there and come back.
there is also no point in talking increased watts as it is the amperage that you will need to deal with with 24 volts this half's so your cable size can reflect this saving you money

 

[john_morris_uk]

The cost of cable is not trivial.
On a big boat, cable which is truly adequate might cost more than two batteries.
Charging 24V batteries from 12V is fairly mundane, at the current needed to keep a battery charged and replenish the use from a pick winch (and/or thruster) it's not expensive.
It's a process as complex or simple as buying a black box from a supplier you trust.
Blathering generalities is not helpful.
To counter what another poster said, 24V equipment is common as muck, lorries are full of it.
The proper thing to do is to fully cost the various schemes and weigh up the pros and cons.
The hidden cost might be the work involved in installing adequate cables which the boat isn't designed around.
I'd guess a 12V windlass with simple fat cables might be the cheapest and best solution, but if one wants a big powerful windlass to cope with a big anchor and lots of chain, maybe not.

No blathering generalities.

The cost of two ten metre lengths of 110 amp cable is less than £100. https://www.12voltplanet.co.uk/extra-flexible-tinned-copper-pvc-batterywelding-cable-16mm-110a.html. (I’ve quoted that because it’s what I’ve got feeding our Lofrans X2 from the main domestic batteries and it works perfectly.)

I don’t know where you buy your batteries but that doesn’t get near to buying just one of the deep discharge heavy duty batteries required.

I agree that 24v kit is common as muck but the OP hasn’t got a 24v boat and buying a black box if the shelf 12v to 24v power converter isn’t cheap either at the lower levels required. Up to a few amps they’re cheap as chips but for serious power (eg to run a windlass) they’re megabucks.

I agree that charging a 24 volt battery bank from 12v is easy but you’re lining yourself up for all sorts of problems if you are in a critical repeated anchoring situation. Occasional use of a bow thruster is fine (it’s not the end of the world if you lose it while the batteries recharge) but losing the ability to weigh anchor etc is a whole different ball game.

I’m all for weighing up the various options but other people have pointed out the additional problems of having all the extra weight in the bow of the boat. (It’s a free world but IMHO extra batteries in the bow are an abomination. )

Perhaps I should have made my post longer and more explicit.

 

[lw395]

No blathering generalities.

The cost of two ten metre lengths of 110 amp cable is less than £100. https://www.12voltplanet.co.uk/extra-flexible-tinned-copper-pvc-batterywelding-cable-16mm-110a.html. (I’ve quoted that because it’s what I’ve got feeding our Lofrans X2 from the main domestic batteries and it works perfectly.)

I don’t know where you buy your batteries but that doesn’t get near to buying just one of the deep discharge heavy duty batteries required.

I agree that 24v kit is common as muck but the OP hasn’t got a 24v boat and buying a black box if the shelf 12v to 24v power converter isn’t cheap either at the lower levels required. Up to a few amps they’re cheap as chips but for serious power (eg to run a windlass) they’re megabucks.

I agree that charging a 24 volt battery bank from 12v is easy but you’re lining yourself up for all sorts of problems if you are in a critical repeated anchoring situation. Occasional use of a bow thruster is fine (it’s not the end of the world if you lose it while the batteries recharge) but losing the ability to weigh anchor etc is a whole different ball game.

I’m all for weighing up the various options but other people have pointed out the additional problems of having all the extra weight in the bow of the boat. (It’s a free world but IMHO extra batteries in the bow are an abomination. )

Perhaps I should have made my post longer and more explicit.

The last windlass I looked at drew 170A.
Taking your arbitrary 2 x 10m and the cable you suggest, I make that 4V dropped.
But only while the copper stays cool, soon it will increase....

 

[john_morris_uk]

The last windlass I looked at drew 170A.
Taking your arbitrary 2 x 10m and the cable you suggest, I make that 4V dropped.
But only while the copper stays cool, soon it will increase....

In that case let’s compare costs of the larger cabling and the even larger batteries required. The sums still don’t stack up in the way that was suggested so blithely. (We can ignore the problems of weight in the bow for now.)

Or are you being slightly disingenuous and quoting start up current. 170 A is an over 2kw windlass and that’s not common. 1kw is more common and if you are into 2kw windlasses then you’re into larger boats that ought to be 24 volt anyway?

I was being generous with the ten metres as our boat is 11.7 metres long but as a centre cockpit sloop the batteries are in the centre and the cables are more like 6 metres long. I was allowing for a larger boat.